Has this problem been solved correctly?

Question

Discrete Math

Condition.
Given 20 questions, in how many ways can they be placed on 6 tickets of 3 questions each.
Decision.


Confuses a large number in the answer, please check.

Answer 1

Not right. The correct answer is 36212176000.
Why do you mix C and A in your answer? What is the physical meaning?
The answer is C(2.20)*C(3.18)*c(3.15)*c(3.12)*...*C(3.3)/6!
Meaning - we take any 2 questions that do not fall into 18 of the tickets. Then we take three of the 18 that go to the first ticket, then 3 of the remaining 15 that go to the second ticket... and so on. At the end we divide by 6! because the order of the tickets doesn't seem to matter.